Question

A rectangular conduct or $PQRS$ in which the conductor $PQ$ is free to move is shown in figure. The rod $PQ$ is moved towards the left with a constant velocity $v$ as shown in figure. Assume that there is no loss of energy due to friction. $PQRS$ forms a closed circuit enclosing an area that changes as $PQ$ moves. It is placed in a uniform magnetic field $B$ which is perpendicular to the plane of this system.
The length $RQ=x$ and $RS=l$.

The induced emf $Blv$ is called

• A. constant emf
• B. accelerated emf
• C. motional emf
• D. Both (b) and (c)

Answer 1

Answer: (C)

The induced emf $Blv$ is called motional emf. Thus, we are able to produce induced emf by moving a conductor instead of varying the magnetic field, that is by changing the magnetic flux enclosed by the circuit.